mRNA localization and regulated translation play central roles in axon guidance and synaptic plasticity. By spatially restricting gene expression within neurons, local protein synthesis allows growth cones and synapses to autonomously regulate their structure and function. The long-term goals of this project are to understand the cell biology and function of local translation during learning-related neuronal plasticity and during synapse formation. Our experiments are designed to address the following four questions: 1) what mRNAs are present in neuronal processes? 2) How do mRNAs localize within neurons? 3) How is translation of localized transcripts regulated at the synapse? And 4) what is the function of specific locally translated proteins in neurons? We address these questions in a well-characterized, experimentally tractable model of synaptogenesis and learning-related synaptic plasticity: cultured Aplysia sensory-motor neurons. Our strategy involves the use of microarray and high throughput sequencing technologies to identify mRNAs that are present in neuronal processes following neuronal stimulation, together with cell biological approaches to visualize mRNA localization and regulated translation in living neurons and RNA interference approaches to study the function of specific localized mRNAs during synapse formation and synaptic plasticity. The results of our proposed experiments will provide insight into the cell biology of mRNA localization within neurons and into the function of specific localized transcripts. PUBLIC HEALTH RELEVANCE: We propose to investigate the cell biology underlying the initial wiring of the brain and the changes in brain wiring that occur during learning and memory. The results of our studies will identify genes that are likely to be involved in brain developmental disorders, such as mental retardation, and in the many diseases in which learning and memory are altered. Such diseases include Fragile X Mental Retardation, Spinal Muscular Atrophy, and Alzheimer's disease, epilepsy, drug addiction and many neuropsychiatric disorders.